Conventionally, a process for producing fatty alcohols by catalytically hydrogenating lower alcohol fatty esters obtained by transesterification of fats and oils with a lower monoalcohol, preferably methanol, is used for industrial production of fatty alcohols. Alternatively, a method of catalytically hydrogenating wax esters obtained by esterifying hydrolyzed fatty acids and fatty alcohols is also used. These two-stage processes are economically excellent because valuable glycerin can be obtained with high yield and high purity.
On one hand, the direct catalytic hydrogenation of fats and oils enables an industrially important product fatty alcohol to be directly obtained from naturally occurring fats and oils, but is not so used in industrial production. This is because a side reaction wherein initially formed glycerin is hydrogenated on the surface of a catalyst occurs in the direct catalytic hydrogenation of fats and oils, and thus glycerin cannot be obtained in high yield, so the direct catalytic hydrogenation process cannot compete economically with the 2-stage process. This is one reason that the process of directly hydrogenating fats and oils is not used in industrial scale.
Methods of obtaining a fatty alcohol by directly hydrogenating fats and oils are described in for example U.S. Pat. No. 2,094,127, U.S. Pat. No. 2,109,844 and U.S. Pat. No. 2,241,417. DE-A 1668219 describes a method of hydrogenating fats and oils obtained from fats and oils. U.S. Pat. No. 5,364,986 and U.S. Pat. No. 5,475,160 also describe methods of directly hydrogenating fats and oils, and in these methods, the direct hydrogenation of fats and oils into fatty alcohols is conducted by using a copper-based catalyst under relatively mild reaction conditions.